Dental anxiety (DA) is a prevalent public health issue. However, there is a lack of self-administered DA interventions. The aim of this study was to evaluate the short-term effects of web-based interventions aiming to reduce DA in adults in two European countries. A pretest posttest design was used. Tailor-made websites were developed in Lithuania and Norway. Volunteers who self-reported DA were invited to participate. DA levels measured by the Modified Dental Anxiety Scale (MDAS) were assessed at baseline and after two weeks via online questionnaires. The interventions were completed by 34 participants in Lithuania and 35 participants in Norway. In Lithuania, the median posttest MDAS score (9.5, IQR 5.25) decreased compared to the median pretest MDAS score (14.5, IQR 8; Z value = −4.246, p < 0.001). The same was found in Norway—the median posttest MDAS score (12, IQR 9) was lower compared to the median pretest MDAS score (15, IQR 7; Z value = −3.818, p < 0.001). The present study demonstrated that two tailor-made web-based interventions had the potential to reduce dental anxiety levels when assessed in the short term in Lithuania and Norway. Studies with more controlled designs assessing long-term outcomes are needed to validate the results of this pilot study also in other cultures.